﻿using System.Drawing;
using System.Drawing.Imaging;
using System.Numerics;
using System.Runtime.Versioning;
using FFMpegCore.Extensions.System.Drawing.Common;
using FFMpegCore.Pipes;
using SkiaSharp;

namespace FFMpegCore.Test.Utilities;

internal static class BitmapSource
{
    [SupportedOSPlatform("windows")]
    public static IEnumerable<IVideoFrame> CreateBitmaps(int count, PixelFormat fmt, int w, int h)
    {
        for (var i = 0; i < count; i++)
        {
            using (var frame = CreateVideoFrame(i, fmt, w, h, 0.025f, 0.025f * w * 0.03f))
            {
                yield return frame;
            }
        }
    }

    public static IEnumerable<IVideoFrame> CreateBitmaps(int count, SKColorType fmt, int w, int h)
    {
        for (var i = 0; i < count; i++)
        {
            using (var frame = CreateVideoFrame(i, fmt, w, h, 0.025f, 0.025f * w * 0.03f))
            {
                yield return frame;
            }
        }
    }

    [SupportedOSPlatform("windows")]
    public static BitmapVideoFrameWrapper CreateVideoFrame(int index, PixelFormat fmt, int w, int h, float scaleNoise, float offset)
    {
        var bitmap = new Bitmap(w, h, fmt);

        foreach (var (x, y, red, green, blue) in GenerateVideoFramePixels(index, w, h, scaleNoise, offset))
        {
            var color = Color.FromArgb(red, blue, green);
            bitmap.SetPixel(x, y, color);
        }

        return new BitmapVideoFrameWrapper(bitmap);
    }

    public static Extensions.SkiaSharp.BitmapVideoFrameWrapper CreateVideoFrame(int index, SKColorType fmt, int w, int h, float scaleNoise, float offset)
    {
        var bitmap = new SKBitmap(w, h, fmt, SKAlphaType.Opaque);

        bitmap.Pixels = GenerateVideoFramePixels(index, w, h, scaleNoise, offset)
            .Select(args => new SKColor(args.red, args.blue, args.green))
            .ToArray();

        return new Extensions.SkiaSharp.BitmapVideoFrameWrapper(bitmap);
    }

    private static IEnumerable<(int x, int y, byte red, byte green, byte blue)> GenerateVideoFramePixels(int index, int w, int h, float scaleNoise,
        float offset)
    {
        offset = offset * index;

        for (var y = 0; y < h; y++)
        {
            for (var x = 0; x < w; x++)
            {
                var xf = x / (float)w;
                var yf = y / (float)h;
                var nx = x * scaleNoise + offset;
                var ny = y * scaleNoise + offset;

                var value = (byte)((Perlin.Noise(nx, ny) + 1.0f) / 2.0f * 255);

                yield return (x, y, (byte)(value * xf), (byte)(value * yf), value);
            }
        }
    }

    //
    // Perlin noise generator for Unity
    // Keijiro Takahashi, 2013, 2015
    // https://github.com/keijiro/PerlinNoise
    //
    // Based on the original implementation by Ken Perlin
    // http://mrl.nyu.edu/~perlin/noise/
    //
    private static class Perlin
    {
        #region Noise functions

        public static float Noise(float x)
        {
            var X = (int)MathF.Floor(x) & 0xff;
            x -= MathF.Floor(x);
            var u = Fade(x);
            return Lerp(u, Grad(perm[X], x), Grad(perm[X + 1], x - 1)) * 2;
        }

        public static float Noise(float x, float y)
        {
            var X = (int)MathF.Floor(x) & 0xff;
            var Y = (int)MathF.Floor(y) & 0xff;
            x -= MathF.Floor(x);
            y -= MathF.Floor(y);
            var u = Fade(x);
            var v = Fade(y);
            var A = (perm[X] + Y) & 0xff;
            var B = (perm[X + 1] + Y) & 0xff;
            return Lerp(v, Lerp(u, Grad(perm[A], x, y), Grad(perm[B], x - 1, y)),
                Lerp(u, Grad(perm[A + 1], x, y - 1), Grad(perm[B + 1], x - 1, y - 1)));
        }

        public static float Noise(Vector2 coord)
        {
            return Noise(coord.X, coord.Y);
        }

        public static float Noise(float x, float y, float z)
        {
            var X = (int)MathF.Floor(x) & 0xff;
            var Y = (int)MathF.Floor(y) & 0xff;
            var Z = (int)MathF.Floor(z) & 0xff;
            x -= MathF.Floor(x);
            y -= MathF.Floor(y);
            z -= MathF.Floor(z);
            var u = Fade(x);
            var v = Fade(y);
            var w = Fade(z);
            var A = (perm[X] + Y) & 0xff;
            var B = (perm[X + 1] + Y) & 0xff;
            var AA = (perm[A] + Z) & 0xff;
            var BA = (perm[B] + Z) & 0xff;
            var AB = (perm[A + 1] + Z) & 0xff;
            var BB = (perm[B + 1] + Z) & 0xff;
            return Lerp(w, Lerp(v, Lerp(u, Grad(perm[AA], x, y, z), Grad(perm[BA], x - 1, y, z)),
                    Lerp(u, Grad(perm[AB], x, y - 1, z), Grad(perm[BB], x - 1, y - 1, z))),
                Lerp(v, Lerp(u, Grad(perm[AA + 1], x, y, z - 1), Grad(perm[BA + 1], x - 1, y, z - 1)),
                    Lerp(u, Grad(perm[AB + 1], x, y - 1, z - 1), Grad(perm[BB + 1], x - 1, y - 1, z - 1))));
        }

        public static float Noise(Vector3 coord)
        {
            return Noise(coord.X, coord.Y, coord.Z);
        }

        #endregion

        #region fBm functions

        public static float Fbm(float x, int octave)
        {
            var f = 0.0f;
            var w = 0.5f;
            for (var i = 0; i < octave; i++)
            {
                f += w * Noise(x);
                x *= 2.0f;
                w *= 0.5f;
            }

            return f;
        }

        public static float Fbm(Vector2 coord, int octave)
        {
            var f = 0.0f;
            var w = 0.5f;
            for (var i = 0; i < octave; i++)
            {
                f += w * Noise(coord);
                coord *= 2.0f;
                w *= 0.5f;
            }

            return f;
        }

        public static float Fbm(float x, float y, int octave)
        {
            return Fbm(new Vector2(x, y), octave);
        }

        public static float Fbm(Vector3 coord, int octave)
        {
            var f = 0.0f;
            var w = 0.5f;
            for (var i = 0; i < octave; i++)
            {
                f += w * Noise(coord);
                coord *= 2.0f;
                w *= 0.5f;
            }

            return f;
        }

        public static float Fbm(float x, float y, float z, int octave)
        {
            return Fbm(new Vector3(x, y, z), octave);
        }

        #endregion

        #region Private functions

        private static float Fade(float t)
        {
            return t * t * t * (t * (t * 6 - 15) + 10);
        }

        private static float Lerp(float t, float a, float b)
        {
            return a + t * (b - a);
        }

        private static float Grad(int hash, float x)
        {
            return (hash & 1) == 0 ? x : -x;
        }

        private static float Grad(int hash, float x, float y)
        {
            return ((hash & 1) == 0 ? x : -x) + ((hash & 2) == 0 ? y : -y);
        }

        private static float Grad(int hash, float x, float y, float z)
        {
            var h = hash & 15;
            var u = h < 8 ? x : y;
            var v = h < 4 ? y : h == 12 || h == 14 ? x : z;
            return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
        }

        private static readonly int[] perm =
        {
            151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148, 247,
            120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74,
            165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,
            65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3,
            64, 52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183,
            170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9, 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178,
            185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214,
            31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195,
            78, 66, 215, 61, 156, 180, 151
        };

        #endregion
    }
}
